Sep 17 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Welding
Applications
Introduction
Chromium hot-work tool steels are designated as group H steels by the AISI classification system and this series of steels start from H1 to H19.
H19 chromium hot-work steel has a good resistance to abrasion and wear due to the vanadium content. It is recommended for use in difficult hot work tooling applications such as brass extrusion tooling and brass die casting dies.
The following sections will discuss more about H19 chromium hot-work steels.
Chemical Composition
The table given below shows the chemical composition of H19 tool steels.
| Element |
Content (%) |
| C |
0.32-0.45 |
| Mn |
0.20-0.50 |
| Si |
0.20-0.50 |
| Cr |
4.00-4.75 |
| Ni |
0.3 |
| Cu |
0.25 |
| P |
0.03 |
| S |
0.03 |
| W |
3.75-4.50 |
| Mo |
0.30-0.55 |
| V |
1.75-2.20 |
| Co |
4.00-4.50 |
Physical Properties
The physical properties of H14 tool steels are given in the following table.
| Properties |
Conditions |
| T (°C) |
Treatment |
| Density |
7.98 ×1000 kg/m3 |
25 |
- |
Mechanical Properties
The mechanical properties of H14 tool steels are tabulated below.
| Properties |
Metric |
Imperial |
| Hardness, Rockwell C (air cooled from 1204°C; 704°C temper temperature) |
41 |
41 |
| Hardness, Rockwell C (air cooled from 1204°C; 482°C temper temperature) |
57 |
57 |
| Hardness, Rockwell C (air cooled from 1204°C; 530°C temper temperature) |
58 |
58 |
| Machinability (1% carbon steel) |
55.0 - 60.0% |
55.0 - 60.0% |
Thermal Properties
The following table shows the thermal properties of H14 tool steels.
| Properties |
Conditions |
| T (°C) |
Treatment |
| Thermal expansion |
11 x 10-6/ºC |
20-100 |
- |
Other Designations
Other designations that are equivalent to H14 tool steels include:
- ASTM A681
- FED QQ-T-570
- UNS T20819
Fabrication and Heat Treatment
Machinability
The machinability rate of H19 tool steels is 40% of that of a B1112 steel or 60% of that of a 1% carbon steel.
Welding
H19 tool steels are generally welded by shielded arc methods. They are preheated to 510°C (950°F) before welding. These steels are fully annealed before forming or machining to obtain best results.
Applications
The following are the applications of H19 tool steels:
- Hot dies
- Extrusion inserts for aluminum and brass